It is well known that soaps produced from low-grade fatty materials, such as low-grade tallow often develop an unpleasant odour during storage. It is therefore common in the soap-manufacturing industry either to pre-treat the low-grade fatty material to remove malodorous components therefrom, to use more expensive higher-grade fatty materials or to add perfumes so as to mask the unpleasant malodours. The methods applied to avoid or mitigate the emanation of malodours increase the production costs of toilet soaps.